1. It leads the discussion to extremes at the outset: it invites you to think that animals should be treated either with the consideration humans extend to other humans,or with no consideration at all.
【译文】这种说法从一开始就将讨论引向两个极端，它使人们认为应这样对待动物：要么像对人类自身一样关切体谅，要么完全冷漠无情。
【析句】主句是It leads the discussion to extremes，at the outset作时间状语。冒号后面的成分是对主句进一步说明，其宾语是一个that引导的从句，而在这个从句中，either…or…是一个介词短语，作方式状语。
【讲词】consideration意为“体谅,考虑；需要考虑的事项”。Your proposal is under consideration.（你的提议正在考虑之中。）Face is a big consideration for Chinese.(中国人非常重面子。）He showed no consideration for his wife.（他从不体谅他的妻子。）
extend意为“延伸；延长；扩大；给予”。The bank has promised to extend your company credit.（银行已经答应向你们公司提供信用贷款。）The wet weather extended into September.（潮湿阴雨的天气延续到九月份。）Please accept our sincere thanks for the courtesy extended to our company.（对我们一行所受到的礼遇，我们由衷表示谢意。）
2. Arguing from the view that humans are different from animals in every relevant respect,extremists of this kind think that animals lie outside the area of moral choice.
【译文】 这类极端主义者认为人与动物在各相关方面都不相同，对待动物无须考虑道德问题。
【析句】 现在分词结构（Arguing from the view that humans are different from animals in every relevant respect）作状语，主干结构是extremists of this kind think，宾语是一个从句。
animals lie outside the area of moral choice直译是“动物是在道德选择的范畴之外”，即“对待动物无须考虑道德问题”。
【讲词】 respect作名词时除了“尊重”之外，还可表示“方面”，例如：In many respects this is an important decision.（这在许多方面都是一项重要的决定。）In this respect,I would argue that this is the only decision which could have been made.（从这一方面来说，我认为这是唯一可作的决定。）